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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Global Distribution of Extreme Precipitation and High-Impact Landslides in 2010 Relative to Previous Years

It is well known that extreme or prolonged rainfall is the dominant trigger of landslides worldwide. While research has evaluated the spatiotemporal distribution of extreme rainfall and landslides at local or regional scales using in situ data, few studies have mapped rainfall-triggered landslide distribution globally due to the dearth of landslide data and consistent precipitation information. This study uses a newly developed Global Landslide Catalog (GLC) and a 13-year satellite-based precipitation record from TRMM data. For the first time, these two unique products provide the foundation to quantitatively evaluate the co-occurrence of precipitation and landslides globally. Evaluation of the GLC indicates that 2010 had a large number of high-impact landslide events relative to previous years. This study considers how variations in extreme and prolonged satellite-based rainfall are related to the distribution of landslides over the same time scales for three active landslide areas: Central America, the Himalayan Arc, and central-eastern China. Several test statistics confirm that TRMM rainfall generally scales with the observed increase in landslide reports and fatal events for 2010 and previous years over each region. These findings suggest that the co-occurrence of satellite precipitation and landslide reports may serve as a valuable indicator for characterizing the spatiotemporal distribution of landslide-prone areas in order to establish a global rainfall-triggered landslide climatology. This study characterizes the variability of satellite precipitation data and reported landslide activity at the globally scale in order to improve landslide cataloging, forecasting and quantify potential triggering sources at daily, monthly and yearly time scales.

Kirschbaum, Dalia↗
NASA NTRS2001

Measurement of the Vertical Distribution of Aerosol by Globally Distributed MP Lidar Network Sites

The global distribution of aerosol has an important influence on climate through the scattering and absorption of shortwave radiation and through modification of cloud optical properties. Current satellite and other data already provide a great amount of information on aerosol distribution. However there are critical parameters that can only be obtained by active optical profiling. For aerosol, no passive technique can adequately resolve the height profile of aerosol. The aerosol height distribution is required for any model for aerosol transport and the height resolved radiative heating/cooling effect of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched by 2002. GLAS will provide global measurements of the height distribution of aerosol. The sampling will be limited by nadir only coverage. There is a need for local sites to address sampling, and accuracy factors. Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently six sites in operation and over a dozen planned. At all sites there are a complement of passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The aerosol measurements, retrievals and data products from the network sites will be discussed. The current and planned application of data to supplement satellite aerosol measurements is covered.

Spinhirne, James↗
NASA NTRS1991

Atlas of the global distribution of atmospheric heating during the global weather experiment

Global distributions of atmospheric heating for the annual cycle of the Global Weather Experiment are estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) Level 3b data set. Distributions of monthly, seasonally, and annually averaged heating are presented for isentropic and isobaric layers within the troposphere and for the troposphere as a whole. The distributions depict a large-scale structure of atmospheric heating that appears spatially and temporally consistent with known features of the global circulation and the seasonal evolution.

Schaack, Todd K.↗
NASA NTRS1991

The global distribution of Martian permafrost

Accurately determining the present global distribution of Martian ground ice will be an important step towards understanding the evolution of the Martian surface and atmosphere, and could greatly facilitate human and robotic exploration of the planet. The quantitative Mars permafrost studies demonstrated the potential importance of a number of factors determining the past and present distribution of subsurface ice on Mars, but have not considered the issue of regional variability. To consider the distribution of Mars permafrost in greater detail a new thermal model was developed that can calculate Martian surface and subsurface temperatures as a function of time-of-day and season. The results indicate that the distribution of Martian permafrost is highly sensitive to the bulk thermal properties of the overlying soil. Viking IRTM observations of diurnal surface temperature variations show that the bulk thermal properties of midlatitude surface materials exhibit a high degree of regional inhomogeneity. In general, the results show that the global distribution of permafrost is at least as sensitive to the thermal properties of the overlying surface material as it is to variations in surface isolation due to large scale variations in Mars' orbital and axial elements. In particular, they imply that subsurface ice may exist just a few centimeters below the surface in regions of low thermal inertia and high albedo, which are widespread at latitudes ranging from the equator to +60 degrees latitude.

Paige, David A.↗
NASA NTRS1986

Global distribution of midnight lightning - September 1977 to August 1978

A detailed study is reported of the distribution of global midnight lightning from 60 deg S to 60 deg N for 365 consecutive days. The period covered is from September 1, 1977, to August 31, 1978. More than 32,000 lightning locations obtained from DMSP photographic data are plotted with an accuracy of 100 km. The locations are in good agreement with features of the general circulation. Land-ocean lightning ratios vary from 2.2 (September) to 4.2 (July) with a mean of 3.2. If these values are corrected for the earth's land-ocean area ratio of 1/2.4, the land-ocean lightning ratios range from 5.3 (September) to 10 (July) with a mean of 7.7.

Orville, Richard E.↗
NASA NTRS2006

First Directly Retrieved Global Distribution of Tropospheric Column Ozone from GOME: Comparison with the GEOS-CHEM Model

We present the first directly retrieved global distribution of tropospheric column ozone from Global Ozone Monitoring Experiment (GOME) ultraviolet measurements during December 1996 to November 1997. The retrievals clearly show signals due to convection, biomass burning, stratospheric influence, pollution, and transport. They are capable of capturing the spatiotemporal evolution of tropospheric column ozone in response to regional or short time-scale events such as the 1997-1998 El Nino event and a 10-20 DU change within a few days. The global distribution of tropospheric column ozone displays the well-known wave-1 pattern in the tropics, nearly zonal bands of enhanced tropospheric column ozone of 36-48 DU at 20degS-30degS during the austral spring and at 25degN-45degN during the boreal spring and summer, low tropospheric column ozone of <30 DU uniformly distributed south of 35 S during all seasons, and relatively high tropospheric column ozone of >33 DU at some northern high-latitudes during the spring. Simulation from a chemical transport model corroborates most of the above structures, with small biases of <+/-5 DU and consistent seasonal cycles in most regions, especially in the southern hemisphere. However, significant positive biases of 5-20 DU occur in some northern tropical and subtropical regions such as the Middle East during summer. Comparison of GOME with monthly-averaged Measurement of Ozone and Water Vapor by Airbus in-service Aircraft (MOZAIC) tropospheric column ozone for these regions usually shows good consistency within 1 a standard deviations and retrieval uncertainties. Some biases can be accounted for by inadequate sensitivity to lower tropospheric ozone, the different spatiotemporal sampling and the spatiotemporal variations in tropospheric column ozone.

Liu, Xiong↗
NASA NTRS1991

Ground based infrared measurements of the global distribution of ozone in the atmosphere of Mars

The global distribution of ozone in the atmosphere of Mars was determined from Doppler-limited infrared heterodyne spectroscopy measurements at the NASA Infrared Telescope Facility (IRTF) facility during June 3-7, 1988. Mars spectra near two O3 lines arising from the v sub 3 band near 1031.45 cm (-1) were used. The lines were Doppler shifted out of the strong terrestrial ozone absorption spectrum and its effect was removed. Ozone measurements were obtained at eight beam positions over a range of latitudes and local solar zenith angles. The beam size of the planet was 1.4 arcsec. A Martian CO2 line appeared in the spectra and was inverted to retrieve local temperature profiles. Using these temperature profiles, the total ozone column abundance at each position was retrieved by fitting the measured line with synthetic spectra generated by a radiative transfer program. The only previous measurement of ozone at this season was made above the South polar cap by Mariner 7 and revealed an abundance of 10 micron-atm. However, the retrieved O3 column abundances from this investigation are less than 2.2 micron-atm at all positions sampled. These results are consistent with mid-spring abundances predicted by photochemical models of Liu and Donahue, and Shimazaki and Shimizu.

Kostiuk, Theodor↗
NASA NTRS1985

Measuring the global distribution of intense convection over land with passive microwave radiometry

The global distribution of intense convective activity over land is shown to be measurable with satellite passive-microwave methods through a comparison of an empirical rain rate algorithm with a climatology of thunderstorm days for the months of June-August. With the 18 and 37 GHz channels of the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR), the strong volume scattering effects of precipitation can be measured. Even though a single frequency (37 GHz) is responsive to the scattering signature, two frequencies are needed to remove most of the effect that variations in thermometric temperatures and soil moisture have on the brightness temperatures. Because snow cover is also a volume scatterer of microwave energy at these microwavelengths, a discrimination procedure involving four of the SMMR channels is employed to separate the rain and snow classes, based upon their differences in average thermometric temperature.

Spencer, R. W.↗
NASA NTRS1986

Global distribution of SAGE II data products

Techniques employed to map the global distribution of stratospheric aerosols using SAGE II data at four wavelengths (385, 453, 525 and 1020 microns) are described. The methods were devised to integrate the 900 data points scanned by the instrument with account taken of the different times the vertical profiles were obtained. The data have been used to calculate the O3, H2O, NO2 and aerosol optical thicknesses. Sample details of data gathered during April 1985 are discussed, with emphasis on difficulties being encountered in analyzing the differences being observed in the dawn and dusk data.

Rind, D.↗
NASA NTRS1994

January and July global distributions of atmospheric heating for 1986, 1987, and 1988

Three-dimensional global distributions of atmospheric heating are estimated for January and July of the 3-year period 1986-88 from the European Center for Medium Weather Forecasts (ECMWF) Tropical Ocean Global Atmosphere (TOGA) assimilated datasets. Emphasis is placed on the interseasonal and interannual variability of heating both locally and regionally. Large fluctuations in the magnitude of heating and the disposition of maxima/minima in the Tropics occur over the 3-year period. This variability, which is largely in accord with anomalous precipitation expected during the El Nino-Southern Oscillation (ENSO) cycle, appears realistic. In both January and July, interannual differences of 1.0-1.5 K/day in the vertically averaged heating occur over the tropical Pacific. These interannual regional differences are substantial in comparison with maximum monthly averaged heating rates of 2.0-2.5 K/day. In the extratropics, the most prominent interannual variability occurs along the wintertime North Atlantic cyclone track. Vertical profiles of heating from selected regions also reveal large interannual variability. Clearly evident is the modulation of the heating within tropical regions of deep moist convection associated with the evolution of the ENSO cycle. The heating integrated over continental and oceanic basins emphasizes the impact of land and ocean surfaces on atmospheric energy balance and depicts marked interseasonal and interannual large-scale variability.

Schaack, Todd K.↗
NASA NTRS1992

Global distributions of upper tropospheric relative humidity derived from SAGE II observations

The global distributions of upper tropospheric relative humidity derived from the archived SAGE II water vapor data set are presented. For both summer and winter months, vertical profiles of zonal mean relative humidity are derived for each of the six 20-deg latitude bands covering 60 deg N - 60 deg S. Some examples of global maps of upper tropospheric relative humidity are shown to illustrate the relationship between moist areas and convective activity.

Chiou, E. W.↗
NASA NTRS2001

Aerosol Measurements by the Globally Distributed Micro Pulse Lidar Network

Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide full time profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently eight sites in operation and over a dozen planned. At all sited there are also passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The network operation includes instrument operation and calibration and the processing of aerosol measurements with standard retrievals and data products from the network sites. Data products include optical thickness and extinction cross section profiles. Application of data is to supplement satellite aerosol measurements and to provide a climatology of the height distribution of aerosol. The height distribution of aerosol is important for aerosol transport and the direct scattering and absorption of shortwave radiation in the atmosphere. Current satellite and other data already provide a great amount of information on aerosol distribution, but no passive technique can adequately resolve the height profile of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched in early 2002. GLAS will provide global measurements of the height distribution of aerosol. The MP lidar network will provide ground truth and analysis support for GLAS and other NASA Earth Observing System data. The instruments, sites, calibration procedures and standard data product algorithms for the MPL network will be described.

Spinhirne, James↗
NASA NTRS1985

On the Global Distribution of Three-Dimensional Eliassen-Palm Fluxes by Stationary Waves

The global distribution of three dimensional EP fluxes is investigated by using statistics for Dec. 1980 to Feb. 1981 and June to August 1981 calculated from operational analyses. Results at 1000 and 150 mb are given. During the Northern Hemisphere (NH) winter strong upward fluxes can be seen at 1000 mb in the lee of the Himalayas and Rockies, windward of the Canadian Rockies in the east Pacific, to the north of the Atlantic stormtrack and over the west Pacific in a region of strong land sea thermal contrast. Upward fluxes also appear near the west coasts of the Southern Hemisphere (SH) subtropical continents regions of strong land sea thermal contrast. At 150 mb (Fig. 1b) the strongest upward flux now occurs south of Alaska. The horizontal fluxes imply poleward propagation from the convection over Indonesia to 20 N, a region where the assumptions underlying EP fluxes are not well met. Equatorward propagation dominates the NH midlatitude except over the Pacific. The fluxes given offer hints of the sources of stationary waves, but also show several puzzling features and a rather cavalier disregard of regions of easterly wind. The physical meaning and interpretation of three dimensional EP fluxes is not yet clear.

White, G. H.↗
NASA NTRS2014

Global Distribution and Trends of Tropospheric Ozone: An Observation-Based Review

Tropospheric ozone plays a major role in Earth's atmospheric chemistry processes and also acts as an air pollutant and greenhouse gas. Due to its short lifetime, and dependence on sunlight and precursor emissions from natural and anthropogenic sources, tropospheric ozone's abundance is highly variable in space and time on seasonal, interannual and decadal time-scales. Recent, and sometimes rapid, changes in observed ozone mixing ratios and ozone precursor emissions inspired us to produce this up-to-date overview of tropospheric ozone's global distribution and trends. Much of the text is a synthesis of in situ and remotely sensed ozone observations reported in the peer-reviewed literature, but we also include some new and extended analyses using well-known and referenced datasets to draw connections between ozone trends and distributions in different regions of the world. In addition, we provide a brief evaluation of the accuracy of rural or remote surface ozone trends calculated by three state-of-the-science chemistry-climate models, the tools used by scientists to fill the gaps in our knowledge of global tropospheric ozone distribution and trends.

Mixing ratios↗
NASA NTRS1979

Global distribution of ozone for various seasons

A technique which was used to obtain a catalog of the seasonal global distribution of ozone is presented. The technique is based on the simultaneous use of 1964-1975 data on the total ozone content from a worldwide network of ozonometric stations and on the vertical ozone profile from ozone sounding stations.

Koprova, L. I.↗